Protective effect of beta blockers in postmenopausal women: influence on fractures, bone density, micro and...

Animal studies suggest that bone remodeling is under beta-adrenergic control via the sympathetic nervous system. beta blockers have been suggested to stimulate bone formation and/or inhibit bone resorption in animals as well as to reduce the risk of fracture in humans. The purpose of this study was to examine if these agents can have a preventive or therapeutic effect in osteoporosis.

We have studied the association of beta blockers use with BMD, bone geometry, microarchitecture and fractures rates in postmenopausal women referred for bone density testing. From a total sample of 944 women, we identified 158 women who were taking beta blockers and 341 age-matched women as controls. Bone geometry was investigated at the femoral neck on DXA images. Microarchitecture was evaluated by the H mean fractal parameter at the calcaneus.

The odds ratio for fracture (at all sites) in the beta blocker users was 0.56 (95% CI, 0.30-0.99). beta blocker use was associated with a higher BMD at the femoral neck (+4.2%, p<0.05) and L1-L4 (+3.2%, p<0.05). Proximal femur scans revealed significantly higher cortical width (+3.6%, p<0.05) at the femoral neck under beta blockers. Femoral shaft measurement did not significantly differ under beta blockers. Medication use and lifestyle factors indicated no association between beta blockers and smoking, alcohol use, physical activity, corticosteroids and estrogen therapies. The H mean parameter was significantly higher in the beta blockers group (0.619+/-0.029 vs. 0.607+/-0.023 in controls, p<0.05), suggesting a better trabecular microarchitectural organization.

Our data suggest that the association of current use of beta blockers with low fracture risk is mediated, at least in part, by effects on BMD, cortical bone geometry and trabecular bone microarchitecture.